Big falls in air pollution recorded in both outer and inner London since expansion of low-emissions zone to cover whole of the capital

A new City Hall report shows there have been “substantial improvements” to air quality in outer London and across the capital since the Ultra Low Emissions Zone (Ulez) was expanded in 2023.

The ‘London-wide Ulez One Year Report’, which City Hall says has been “extensively reviewed by an independent advisory group of experts”, reveals that particle emissions (PM2.5) from vehicle exhausts were estimated to be 31% lower in outer London in 2024 than they would have been without the Ulez expansion.

Alongside NO2 and PM2.5 reductions, NOx (nitrogen oxides) emissions from cars and vans were also estimated to be 14% lower in outer London.

The biggest reductions in NO2 levels have been in central London (54%) but there have also been substantial reductions in inner London (29%) and outer London (24%), the report states.

In London, around 4,000 premature deaths per year were previously attributed to toxic air. Air pollution increases the risk of developing asthma, lung cancer, heart disease and stroke, and there is growing evidence that air pollution exposure increases the risk of developing dementia.

In April 2019, London mayor Sir Sadiq Khan launched Ulez in central London, before it was expanded across inner London in 2021, and finally to cover the whole capital In August 2023, bringing the air quality and associated health benefits to the five million people living in outer London.

The boroughs that have seen the biggest reductions in NOx emissions since the expansion are Sutton, Merton, Croydon, Harrow and Bromley, where harmful emissions are estimated to be around 15% lower in 2024 than would be expected without the expansion to outer London.

NOx emissions from road transport are estimated to be 36% lower across London in 2024.

The report also shows a reduction in carbon emissions since the Ulez expansion, while visitor footfall in outer London is said to have increased by 2%, apparently dispelling fears that the zone would reduce retail and leisure spending.

Khan said:  “When I was first elected, evidence showed it would take 193 years to bring London’s air pollution within legal limits if the current efforts continued. However, due to our transformative policies we are now close to achieving it this year. Today’s report shows that Ulez works, driving down levels of pollution, taking old polluting cars off our roads and bringing cleaner air to millions more Londoners.  

“The decision to expand the Ulez was not something I took lightly, but this report shows it was the right one for the health of all Londoners. It has been crucial to protect the health of Londoners, support children’s lung growth, and reduce the risk of people developing asthma, lung cancer and a host of other health issues related to air pollution.

“With boroughs in outer London seeing some of the biggest reductions in harmful emissions and London’s deprived communities also seeing greater benefits, this report shows why expanding Ulez London-wide was so important. 

“Thanks to Ulez and our other policies, all Londoners are now breathing substantially cleaner air, but there is still more to do, and I promise to keep taking action as we build a greener, fairer London for everyone.”    

Transport for London (TfL) data also shows that Londoners have continued to upgrade their vehicles to cleaner models with 96.7% of vehicles seen driving in London now Ulez compliant, up from 91.6% in June 2023 and 39% in February 2017, when changes associated with the Ulez began.

Also welcoming the news on improving air quality, Green Party London Assembly member Caroline Russell said: “The clean air zone should have been London wide from the start. I’m glad the mayor listened and Londoners are finally breathing cleaner air.

“The success of the Ulez is testimony to the many campaigners who pushed and pushed for action, so that Londoners can trust the air they breathe.

“But the work is far from over. Congestion is still a huge issue and more needs to be done to give people the confidence to ditch their cars for good.”

Jemima Hartshorn, director of clean air campaign group Mums for Lungs, said: “Today is a good day for children, and all of us. Air pollution has been reduced due to the pioneering measures of our mayor and we are so glad about that.

“But air pollution across the country and even London remains too high. Hopefully, the national government will learn from this success and support mayors and councils in stopping pollution from diesel and wood burning making us sick.”

Read the full report:
Visit london.gov.uk/programmes-strategies/environment-and-climate-change/environment-and-climate-change-publications/london-wide-ultra-low-emission-zone-one-year-report

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